Curing light device

ABSTRACT

A curing light device for curing a compound includes a housing and a tip structure configured to be removably coupled with the housing. A light emitting device operable for emitting light in a wavelength range suitable for curing a light curable compound is positioned at the distal end of the tip structure. Electrical components are positioned at the proximal end of the tip structure and coupled with the at least one light emitting device and are configured for engaging complementary electrical components positioned in the housing for providing power to the light emitting device. A portion of the tip structure extends beyond the proximal end of the tip structure and is configured to be received by a feature in the housing for physically aligning the tip structure in the housing and for aligning the electrical components. A power supply circuit is rechargeable and includes an ultracapacitor element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a continuation Application of U.S. patentapplication Ser. No. 12/752,335, filed Apr. 1, 2010, entitled “CURINGLIGHT DEVICE”, which claims the benefit of U.S. Patent Application Ser.No. 61/166,130, filed Apr. 2, 2009, entitled “CURING LIGHT DEVICE”,which applications are incorporated herein by reference in theirentireties.

FIELD OF THE INVENTION

This invention relates to illumination or light devices, and morespecifically to an illumination device that is used for oral and dentalapplications and provides light to illuminate and to cure light-curablecompounds in dental applications.

BACKGROUND OF THE INVENTION

Many illumination devices or light devices exist for use in dental andoral applications. One specific category of dental illumination devicesis directed to hand-held devices that are held in proximity to the mouthof the patient to illuminate an area within the patient's mouth forvarious reasons. One particular usage is directed to curinglight-curable compounds in the mouth. While suitable hand-held lightdevices exist for dental applications, there are often various drawbacksassociated with such light devices, particularly with respect to dentalcuring lights.

Many such dental lights have a body, which contains the light elements,such as light-emitting diodes (LED). A tapered and curved light guide,then interfaces with the end of the body and the light-emitting elementsto capture the light and direct it where desired. Generally, such lightguides are bundles of fiber-optic elements, which operate to capture thelight in the device, away from the patient's mouth, and then forwardthat light to a tip that may be placed at the area of interest within apatient's mouth. While such light guides operate in a suitable manner,they are also very inefficient. Almost half of the light generated inthe device is lost in the transmission from its source down to the tip,through the light guide. Such inefficiency requires a significantlylarge light engine to generate the light needed at the curing site, suchas for curing a compound. In turn, heat is generated, which must beproperly removed and directed away from the light engine. The greaterthe output required by the light engine, the more heat that must beaddressed.

Another issue associated with such dental lights is their sterilization.As may be appreciated, the tip of the dental light is generally broughtinto proximity or into actual contact with the mouth of the patient orsome portion of the mouth. Thus, the tip of the light device is exposedto various germs and bacteria. Accordingly, in order to prevent thepropagation of germs or infection between patients, dental instrumentsare often sterilized, such as by being autoclaved at a very hightemperature. While suggestions and some attempts have been made in theart to move the light engine of a dental light closer to the operatingtip, such attempts have not thoroughly addressed the issue ofsterilization. For example, the temperature at which autoclaving isachieved is potentially damaging to a light engine, such as thelight-emitting elements in an LED array. Accordingly, the issue ofsterilization has not been adequately addressed by existing dentallights, such as dental curing lights.

Another drawback to existing dental lights is directed to their need fora power source. Often times, such lights are actually plugged into abase that then couples to an AC source, such as a wall outlet. Some areconnected directly to an AC wall outlet. Some portable dental lightdevices are not attached to a base, but rather utilize batteries, suchas rechargeable batteries. However, rechargeable batteries require asignificant amount of time to charge, and thus, there may be somevaluable down time required for the dental light, when it mightotherwise be put to use. Furthermore, existing battery chargingtechnology uses batteries that are subject to a somewhat limited numberof charge cycles. Their continued ability to take and maintain a chargeis reduced over time and usage. After a somewhat limited number ofcycles, the batteries have to be replaced. Thus, there is still a needto address power issues in portable curing lights.

As such, various drawbacks remain in the field of dental lights,particularly dental curing lights, which are not addressed by thecurrent art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a light device incorporating features of thepresent invention.

FIG. 1A is a perspective view of a light device in a charging base.

FIG. 2 is an exploded cross-sectional view of the light device of FIG.1.

FIG. 2A is an enlarged view of a portion of FIG. 2.

FIG. 3 is a side cross-sectional view of the light device of FIG. 1showing the tip structure engaging the housing.

FIG. 4 is a partial cross-sectional view of an alternative embodiment ofthe light device of the invention.

FIG. 5 is a plan view of an end cap structure for a tip structure of theinvention.

FIG. 6 is a circuit schematic for a charging circuit to be used tocharge the invented light device.

FIG. 7 is a graphical depiction of the curve for operation of thecircuit of FIG. 7.

FIG. 8 is a graphical depiction of the charging of the ultracapacitorsaccording to an embodiment of the invention.

FIG. 9A is a graphical depiction of a capacitor charging curve.

FIG. 9B is a graphical depiction of a capacitor discharging curve.

FIG. 10 is a circuit schematic showing a power supply current sourcecircuit for one embodiment of the invention.

FIG. 11 is a circuit schematic showing a power supply current sourcecircuit for another embodiment of the invention.

FIG. 12 is a circuit schematic showing a power supply current sourcecircuit for another embodiment of the invention.

FIG. 13 is a circuit schematic showing a power supply current sourcecircuit for another embodiment of the invention.

FIG. 14 is a graphical depiction of a discharge function according to anembodiment of the invention.

FIG. 15 is a circuit schematic showing a power supply current sourcecircuit for another embodiment of the invention.

FIG. 16 is a circuit schematic showing a power supply current sourcecircuit for another embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention and,together with a general description of the invention given below, serveto explain the principles of the invention.

FIG. 1 illustrates one embodiment of a light device 10 of the presentinvention. While one embodiment of light device 10 might be used forcuring, other uses are also anticipated, such as illumination, toothwhitening, or other treatment applications. Thus, the present inventionis not limited to the particular use described herein for an exemplaryembodiment. Curing device 10 includes the housing 12 and a tip structure14 that is removably coupled to the housing 12. In accordance with oneaspect of the invention, as discussed further hereinbelow, the tipstructure 14 may be removed so that it may be separately autoclaved fromthe overall device. Device 10 also includes suitable control electronics16 (See FIG. 2) with external controls 18 that may include buttons,switches, or other suitable manual controls for controlling device 10. Adisplay device 20 might also be utilized and may include a screen,individual light elements, or other graphical elements for providing avisual display of the operation of device 10. For example, theoperational mode or setting of the device, the selectable curing times,the remaining curing time, the charging or power status, and diagnosticgraphics might also be illustrated utilizing a visual display 20. Thetip structure 14 includes a proximal end 22 that is removably coupledwith housing 12, and a distal end 24, which is placed within the mouthof a patient for curing a light-curable compound, in accordance with theinvention. The base 26 of housing 12 might be coupled to a suitableexternal power supply, such as an AC or DC source in the form of acharging base or dock 27, as shown in FIG. 1A, for charging rechargeableinternal elements of power supply circuit 28 of the device 10 (See FIG.2). Base 26 might also be configured to fit within a suitable structure,such as a standalone, table-mounted base, a mounting structure formounting it on a wall, pole, or chair, or might be incorporated in aportion of a dental chair for holding and charging the curing device 10.

FIGS. 2 and 2A illustrate cross-sectional views of device 10, showingthe interface between the tip structure 14 and housing 12.

FIG. 3 illustrates the tip structure 14 engaging the housing. In thefigures, section lines 30 are shown indicating a removable portion ofthe housing 12 for illustrative purposes. The housing 12, as well as thetip structure 14, may be sized as appropriate for a hand-held curingdevice that may be manipulated to position the distal end 24 of thedevice in the mouth of a patient, or otherwise proximate tolight-curable material and compounds.

Tip structure 14 includes a heat sink structure or element 32 thatextends in the tip structure from the proximal end 22 to the distal end24. In one embodiment of the invention, as illustrated in FIGS. 2 and2A, the heat sink 32 extends past the proximal end 22 of the tipstructure 14 to engage the housing 12 for appropriate thermal transferof heat from a curing light device. The heat sink may be made from asuitable heat-transfer or heat-conducting material, such as a metal(e.g. copper) or aluminum. Alternatively, a high thermal conductivitymaterial such as Pyrolytic Graphite sheets (PGS) might be used for heatsink 32. In one embodiment, the heat sink 32 is an elongated copper tubeformed in an appropriate shape for positioning inside the tip structure14. Suitable thermal insulation material 34 surrounds the heat sink 32.Tip structure 14 includes a body 36 that houses the elements of the tipstructure, and is appropriately sealed at its proximal and distal ends22 and 24, as discussed further hereinbelow. The body 36 is made from anautoclavable material in accordance with one aspect of the invention. Asnoted above, it is desirable to sterilize certain reusable dentalelements, such as those that are used in or inserted into or onto orproximate to the mouth of a patient. Past curing light devices have notbeen autoclavable to the degree desired by dental professionals. Thepresent invention provides the tip structure enclosed within a sealedbody 36 made from an autoclavable material that is able to withstandhigh temperature autoclaving, such as above 121° C., thus making theentire tip structure, including the light-emitting device or enginetherein, autoclavable as well.

In one embodiment of the invention, the autoclavable body 36 is formedof a suitable metal, such as stainless steel. Alternatively, the body 36might be formed of a ceramic, glass, or porcelain material that is ableto withstand the temperatures associated with autoclaving. Generally,the body 36 will be formed to a suitable shape in conjunction with theheat sink 32 and insulation material 34. For example, the heat sink 32and insulation material 34 might be formed and the body 36 then formedby coating with the ceramic, glass porcelain, or other autoclavablematerial. In the embodiment illustrated in the figures, the tipstructure 14 is appropriately curved from manipulation at a curing site,such as the mouth of a patient, and thus, the body 36 is formed in acurved fashion as well.

Coupled at the distal end of the heat sink 32 is a light-emittingdevice, or light-emitting engine 40. Such light-emitting devices mayinclude one or more LED elements that are known for curing light-curablecompounds, such as dental compounds, and are available from variousmanufacturers. High power LED elements are one suitable type of elementsfor the inventive device. For example, a high-power dental LED might beused. The light-emitting engine might use a single LED element or aplurality of elements in an array. Generally, for curing purposes, thelight-emitting device will emit a light in a particular desiredwavelength for curing a light-curable compound. For various dentalcompounds, a suitable light is in the wavelength range of 400-500nanometers, or the blue light range. For other uses of the inventivelight, such as for examination of the oral regions to detect caries,illuminate areas, and provide cancer screening, other wavelengths mightbe used.

However, in accordance with another aspect of the invention, variousdifferent tip structures 14 may be readily removed and inserted into thehousing 12 so that multiple different tip structures might be utilizedwith a single housing 12. To that end, the light-emitting devices of thevarious tip structures might be directed to other applications, such asto whiten teeth, or for illumination within the mouth of a patient, butwould still be operated with the same housing 12 and its controls. Assuch, the present invention is not limited to a specific type oflighting device or use, and various different tip structures 14 might beutilized with light-emitting devices that emit light in an appropriaterange of wavelengths for different uses, such as curing, whitening,illuminating, screening, etc.

Such light-emitting devices or light engine 40 generally include a baseor substrate 42 that supports one or more light-emitting structures, orsemi-conductor junctions, such as in the form of light-emitting diodesor LEDs. A single light-emitting structure might be utilized or an arrayof structures might be arranged on substrate 42 for providing device 40,depending upon the power of the structures or elements. High power LEDelements may be used for example. The light-emitting device 40 is ableto withstand high temperatures, and thus, utilizes high-temperaturestructures, or LED's. Substrate 42 is adhered directly to the distal endof heat sink 32 utilizing a high-temperature adhesive or cement. Thedirect coupling of the light-emitting device 40 to the heat sink 32provides optimum thermal coupling for removal of the heat generated bythe light-emitting structures 44 or substrate 42.

To seal the distal end 24 of housing 36, a glass window 46 or othertransparent element is solder-sealed around its periphery to housing 36,as shown in FIGS. 2 and 3. The transparent element is configured toallow light to pass out of the distal end of the housing. To that end,the glass window 46 might include metalized portions around itsperiphery for proper solder-sealing to the housing 36 utilizing ahigh-temperature solder, or other appropriate high-temperature adhesive.Generally, the light-emitting device 40 operates with a lens 48 over theLEDs or other light-emitting structures in order to focus the light fromthose structures. A window 46 is illustrated in FIG. 2. Alternatively, aseparate lens 48 might be sealed to the end of the housing 36 instead ofa window 46. The lens 48 may be appropriately shaped for focusing lightfrom light-emitting device 40.

To power the light-emitting device 40, the present invention utilizeshigh-temperature flexible circuits, or flex circuits 50, 52. The flexcircuits extend generally along the inside of the tip structureproximate the heat sink 32. The flex circuits are flexible, and thus,may follow the contour or shape of the heat sink 32. In one embodimentof the invention, suitable traces or channels might be formed in theheat sink 32 for placement of the flex circuits 50, 52. The flexcircuits 50, 52, in turn, couple to a ceramic end cap 54, with suitableelectrically-conductive elements, such as traces, thereon for couplingto the flex circuits, and ultimately to a power supply and controlcircuits, as discussed further below.

Referring now to FIG. 2A, the proximal end 22 of the tip structure 14,and particularly the proximal end of housing 36, is sealed utilizing aceramic end cap 54 that has rotational circuit traces 56, 58 formedtherein, as illustrated in FIG. 5. Specifically, in one particularfeature of the invention, the tip structure 14 is rotatably coupled withhousing 12. To facilitate such rotation, while maintaining the deliveryof electrical signals to the light-emitting device 40, device 10 of theinvention incorporates circular electrically-conductive elements orcircuit traces 56, 58 formed on or in the end cap 54. As illustrated inFIG. 5, the circuit traces 56, 58 generally follow the shape of the endcap, and have a generally circular shape. Furthermore, end cap 54 has anappropriate center opening 60 formed therein for passage of the heatsink 32, as illustrated in FIG. 2A. As illustrated in FIG. 2A, theinnermost circuit trace 56 is illustrated is being electrically-coupledto the flex circuit 50. Similarly, the outer circuit trace 58 on the endcap 54 is coupled with flex circuit 52. End cap 54 may be a ceramic endcap of a suitable ceramic material, such as aluminum oxide. The ceramiccap may be adhered to the body 36. If the body is metal, the edge ofceramic cap 54 may be metalized for soldering the cap to the end of thebody. Alternatively, if the body is made from glass, a suitablehigh-temperature adhesive might be utilized to couple the end cap to theglass body.

As illustrated in FIGS. 2A and 5, the metal traces 56, 58 are formedthrough end cap 54 to present a connection for the flex circuits at thedistal end of the tip structure. When coupled with or plugged intohousing 12, as illustrated in FIG. 2A, the flex circuits 50, 52 via theceramic end cap 54 are coupled to a suitable power supply circuit andcontrols. Specifically, spring contacts 62, 64 are mounted at the end ofhousing 12 that interfaces with tip structure 14. Those spring contacts62, 64 are coupled through appropriate connections or circuits 66, 68back to a suitable power supply circuit 28. The supplied power may thenbe controlled via suitable control circuit 16, such as to control theintensity of the light-emitting device, the duration of itsillumination, and various other parameters associated with theoperational modes of device 10. Housing 12 contains suitable controlcircuitry 16 and a power supply circuit 28, along with the variouselectrical connections/circuits 66, 68 for powering the tip structure 14and the light-emitting device 40 at its distal end. Power supply circuit28, through contacts 70 may be coupled to an external supply of power,such as an AC source or a DC source, for charging elements of the powersupply. For example, as is illustrated in FIG. 1A, a base 27 might holdor dock device 10 for recharging purposes. In one embodiment of theinvention, the power supply circuit includes rechargeable supplyelements, such as a battery, which may be charged and removed from theexternal power source to be manipulated by an operator. In analternative embodiment of the invention, as discussed below with respectto FIG. 4, an ultracapacitor element or circuit might be utilized toprovide the desired power for the light-emitting device 40. Housing 12may be formed of any suitable material, such as plastic or metal, orsome other rigid material.

As illustrated in FIG. 3, when the tip structure 14 is coupled tohousing 12, the contacts 62, 64 engage the circuit elements or traces56, 58 respectively in the end of the tip structure. This electronicallycouples the light-emitting device with the power supply circuit. Becauseof the unique circular pattern of the traces, the tip structure 14 maybe rotated in a range of 0°-360°, while the contacts 62, 64 stillmaintain connection to the traces 56, 58. Alternatively, the circularconductive element might only be contacted over some circular range lessthan 360°, but still allow at least partial rotation. In that way, thetip structure may be rotated without jeopardizing the electricalconnection between the housing 12 and the tip structure 14. Although theelectrically-conductive elements 56, 58 are illustrated as formed on thetip structure and the contact elements 62, 64, as positioned on thehousing, their relative position might be reversed with elements 56, 58on housing 12 and elements 62, 64 on tip structure 14. That is, theelectrically-conductive elements or traces 56, 58 and contact elements62, 64 may be positioned on either of the opposing housing and tipstructure to pass power between the two. In an alternative embodiment,alternate pins and sockets might be used between the housing and tipstructure to electrically couple the light-emitting device and powersupply circuit.

At the same time, the proximal end of the heat sink 32 engages asuitable channel 80 formed in housing 12. The channel 80 is formed by anadditional or secondary heat sink structure or element 82, which ispreferably formed of a suitable metal, such as aluminum. In addition tothe channel 80, the heat sink 82 includes a reservoir portion 84, whichcontains additional heat sink material. That reservoir portion might beall metal to form a metal heat sink. In accordance with one embodimentof the invention, the reservoir portion 84 might be made of metal, butthen contains an amount of phase change material 86. Phase changematerial absorbs the heat from the secondary heat sink structure 82, andchanges phase upon such absorption. For example, one suitable phasechange material might be a paraffin wax that melts as it absorbs heat.This allows a suitable delay in the temperature rise of thelight-emitting device 40 to provide a safe temperature level for thelight-emitting device and the overall tip structure during normal usage.Other phase change materials might also be contained within thereservoir portion 84 of the secondary heat sink structure 82, and thus,the present invention is not limited to a particular phase changematerial 86.

As illustrated in FIG. 3, when the tip structure 14 is plugged into, orotherwise coupled to or engaged with, housing 12, the heat sink 32engages the secondary heat sink structure 82 such that the end of theheat sink 32 is inserted into channel 80 to provide direct thermalconnection or coupling between the heat sink 32 and the secondary heatsink structure 82. In that way, the metal of the secondary heat sinkstructure 82 may absorb the heat conducted by heat sink 32. If thereservoir portion 84 is simply solid metal or filled with a metalmaterial, that metal would absorb heat, and thus, keep the temperatureof the light-emitting device at a suitable operating point.Alternatively, if the phase change material 86 fills reservoir 84, thephase change material may melt in its absorption of heat, and thus,change phase to keep the operating point at a suitably low temperature.The circuits 66, 68 are high temperature circuits, and thus, will besuitable in their proximity to the secondary heat sink structure 82.Furthermore, a jacket of insulation 88 might surround a proportion ofthe secondary heat sink structure 82, such as the reservoir portion 84,and may also surround suitable electronic elements, such as the powersupply circuit 28, and portions of the contacts 70 in order to protectthem from the heat of the second heat sink structure 82.

Solid-liquid phase change materials absorb heat, and their temperaturerises to a point where they change phase (their melting point). Thematerials then absorb additional amounts of heat without gettingsignificantly hotter. When the ambient temperature in the reservoirprovided by the secondary heat sink drops, the phase change material 86solidifies, and thus, releases its stored heat. Therefore, the phasechange material absorbs and emits heat while maintaining a generallyconstant temperature, which is desirable for the hand-held housing 12.

Another suitable phase change material is paraffin wax loaded withcarbon. Once the heat sink engages with the bore hole, or channel 80 ofthe external heat sink, suitable thermal conduction is achieved.

The spring-loaded nature of the spring contacts 62, 64 provides aconsistent and robust electrical connection between housing 12 and thetip structure 14.

Turning to FIG. 4, in accordance with another embodiment of the presentinvention, the power supply circuit 28 incorporates one or moreultracapacitors or super capacitors to provide the power for supplyingthe light-emitting device in the tip structure 14. The one or moreultracapacitors 90 could be utilized to replace batteries in the powersupply circuit 28. The ultracapacitors provide high-energy storage, andare able to deliver power instantly when called upon, such as to powerthe light-emitting device. The ultracapacitors also charge very rapidly,sometimes in seconds, using the charging or charger circuits describedherein in accordance with aspects of the invention. They can also beused to provide a necessary sudden burst of energy for applications ofthe device 10 of the invention. The rapid charging time provided by thepower supply circuit 28 of the invention provides quick-chargeapplications, and eliminates the need for rechargeable batteries, whichmay require hours to fully charge. Furthermore, ultracapacitors havegreater useful life. While a NiMH battery might be charged 500 cycles,or a Li-Ion battery 300 cycles, the present invention usesultracapacitors that might be charged 500,000 cycles. Furthermore, suchultracapacitors that are charged and discharged as described herein donot have a memory (like battery units), have a reduced weight and cost,and do not yield hazardous waste upon disposal. For example, NiMH andLi-Ion batteries weigh significantly more on average thanultracapacitors.

A device 10, utilizing the features of the present invention, may becoupled to a suitable external power source, such as in a power base ordock 27 with sufficient contacts to engage the contacts 70 of device 10(FIG. 1A). The ultracapacitors 90 may be charged and then dischargedover a series of use cycles, such as curing cycles, for the device 10.The device may then be replaced into its charging base, or dock, torecharge the ultracapacitor. Generally, the ultracapacitor elements willnot need replacement during the lifetime of the device 10, as wouldbatteries. Since the ultracapacitors 90 charge very rapidly, the downtime between charging cycles for a device 10 is very short. For example,while a NiMH battery or Li-Ion battery might take around 2.5 hours tocharge fully, an ultracapacitor, as charged in accordance with thecircuits of the invention, might be fully charged in 15 seconds.

FIG. 6 is a circuit schematic of one possible charging or chargercircuit to be utilized within the base unit or dock 27 for chargingdevice 10 and particularly for charging the ultracapacitors that wouldbe provided in one such embodiment of the invention. Charger circuit 100includes a power supply circuit/component 102 that provides suitable DCpower to the circuit. For example, the power supply 102 may be coupledwith an appropriate AC power cord 104 for plugging into an AC outlet,and provides DC power within the range of 5-24 Volts, for example. Anindicator LED 106 might be used to provide an indication that the base27 has power. (See FIG. 1A.) As shown in FIG. 1A, base 27 might alsoinclude indicators 111, 113 for indicating that device 10 is charging orfully charged. Circuit 100 is configured to operate as a current sourcein the form of a current foldback circuit, in accordance with oneembodiment of the present invention. The current foldback circuit 100 isutilized to charge the ultracapacitor power supply circuit 28 of theinvention, and provides a desirable rapid charge of the ultracapacitorelements 90 that differs from over how the capacitor might be chargedgenerally. Specifically, in one embodiment of the invention, a currentsource is utilized to charge the ultracapacitor elements 90.

FIGS. 9A and 9B illustrate typical charge and discharge curves for aregular capacitor. For example, FIG. 9A shows a charge curve, and FIG.9B shows a discharge curve. In general capacitor theory, the charge anddischarge curves of a capacitor are considered to be exponential, asillustrated in FIGS. 9A and 9B. A single time constant, or 1T, indicatesthe amount of time that it takes for a capacitor to charge generally toaround 63% of its full charge. The time for a full charge is expressedas 5T, as may be seen in FIG. 9A. FIG. 9B shows the discharge curve thatis also exponential, wherein the time constant 1T is indicative of thetime it takes to discharge to about 37% of its full charge.

However, in the present invention, it is necessary to chargeultracapacitors faster than traditional charging for the purposes ofefficient use by an operator of the device 10 of the invention. That is,for certain uses, such as for curing dental compounds, it is desirableto charge the ultracapacitor very rapidly to avoid waiting and downtimein the curing process. In accordance with one embodiment of theinvention as shown in FIG. 6, a current source power supply circuit 100is used to charge the ultracapacitor at the desired rate. As illustratedin FIG. 8, the invention provides a rapid, generally non-exponentialcharge function for the ultracapacitor. FIG. 8 illustrates a chargingultracapacitor voltage versus time for the charger circuit of FIG. 6,and it may be seen that a very steep linear slope and charging isprovided by the invention for providing a linear change function, asshown in FIG. 6. This provides significant advantages for the invention.

Returning again to FIG. 6, circuit 100 acts as a linear power supplywith a current foldback function. FIG. 7 illustrates a curve associatedwith the operation of a current foldback supply, as illustrated in FIG.6. When the power supply is connected to be charged, such as when device10 is placed into the charging base 27, current is constant until theultracapacitors are fully charged, and then there is effectively littleor no output current to the ultracapacitors.

Charger circuit 100 utilizes a linear adjustable voltage regulator 108,such as an LM1084IT regulator available from National Semi-Conductor. Incircuit 100, regulator 108 is a standard linear regulator where thecontrol feedback signal is controlled by the transistor Q1 voltage Vbe.The current, through the charging ultracapacitor elements coupled to aconnector 109, develops a voltage across sensing resistors (R3/R4). Whenthe voltage across the sensing resistors is equal to the Vbe oftransistor Q1 (0.6V), the transistor turns ON, and forces the linearvoltage regulator 108 to foldback and limit the current generally to avalue of I=0.6V/R3+R4. Once the ultracapacitors are fully charged, thecurrent is generally or effectively 0 Amps. The capacitor charge timewith such a circuit acting as a current source is illustrated in FIG. 8as approximately T=C(V/I).

The constant power charging topology, as utilized in the invention anddisclosed herein, generally transfers all the available power from thecharging source or base into the energy storage ultracapacitors. Thestraight linear constant current or power delivery can generally providea recharge of the power supply of the invention faster than 1T versushaving to wait up to 5T, as with conventional charging of a capacitor.Effectively, the practical charge time will be set by the maximum peakcurrent that the ultracapacitors can accept.

While FIG. 6 illustrates a charger circuit 100 that is a linear constantcurrent foldback power supply, another alternative embodiment of theinvention for fast ultracapacitor charging is to use a switched modecurrent mode power supply with pulse limit and pulse-by-pulse limit. Inanother embodiment, a lithium Ion (Li-Ion) battery charger might beutilized. Alternatively, a nickel metal hydride (NiMH) battery chargermight also be utilized for the purposes of charging the ultracapacitors.

For the purposes of the invention, various different ultracapacitorsmight be utilized. In one embodiment, the ultracapacitor element orelements has a capacity of around 150 Farad. A range of 50-1,000 Faradmight be suitable for the purposes of the invention. A multi-layerultracapacitor might be utilized, such as one from Illinois Capacitor.Alternatively, ultracapacitors made from carbon nanotubes might also beutilized. In still another embodiment, an ultracapacitor made fromcarbon aerogel might be used. Lithium Ion ultracapacitors might also beutilized and provide significant cycling (e.g., 100,000 cycles) with avery low self-discharge characteristic. Another desirable feature ofultracapacitors is that they may be smaller, thinner, and lighter thanconventional power supplies, such as rechargeable batteries.

In one embodiment of the invention, the device 10 is utilized for curingdental compounds. In such an application, the LEDs that are used for thelight device or engine 40 are generally high-power blue LEDs, such as anarray of such LEDs. Such devices are generally current devices, and thelight output from the LEDs is a direct function of the current providedfrom the power supply. In accordance with one aspect of the invention,to maintain a constant light output, the current to the LED elements orarray 40 should be constant. In one feature of the invention, thepresent invention provides a current source to power the LEDs. That is,the ultracapacitors are discharged as a current source. To that end adesirable discharge function for the ultracapacitors of the invention isa straight linear function, as shown in FIG. 14, where the dischargetime would be:T _(discharge) =C(V1−V2)/I

-   -   Where V1 is the full charge voltage and V2 is the lowest        operating voltage.        In one embodiment of the invention, the power supply to drive        the one or more LED elements or an array making up light engine        40 could be a boost pulse width modulated (PWM) current source,        or a buck PWM current source. Alternatively, a buck-boost PWM        current source might be utilized. Also, a flyback current source        or SEPIC current source might be used as discussed below. A        buck-boost topology would provide a desirable long run time        (discharge time) for device 10 by providing power to the one or        more LED elements when the ultracapacitors are fully charged and        the voltage may be higher than the forward voltage necessary for        the LED. Such a topology then also provides power to the LED        when the charge on the ultracapacitors due to discharge is lower        than the forward voltage for the LED. In one embodiment, using        two 100 F ultracapacitors, 30-40 discharge curing cycles of 10        second each might be achieved on a single charge, for example.

FIG. 10 illustrates one embodiment of a suitable buck-boost converter200 for use in an embodiment of the invention. The embodimentillustrated in FIG. 10 illustrates two ultracapacitors C1, C2.Alternatively, a single ultracapacitor might be utilized. Still further,more than two ultracapacitors might be utilized to realize theinvention, as discussed below. As such, the present invention is notlimited to any particular number of ultracapacitors that might beutilized in the power supply.

Power supply circuit 200 utilizes a PWM integrated circuit U1. U1 iscoupled with inductor L1 and provides power to one or more LEDs. FIG. 10illustrates symbolically a single LED1, however, such a symbol alsocovers an array of multiple LEDs. PWM circuit U1 provides power througha current sensing resistor R3. The power supply might be controlledthrough an ON/OFF switch S1 coupled with a suitable control circuit U3,which provides ON/OFF control and timing functionality for the operationof the LEDs and the light device. Circuit U4 provides a local powersupply for the U3 control circuit. In order to control U1 as a currentsource in the present invention, circuit U2, such as an operationalamplifier, converts the current through the LED, sensed by resistor R3,into a feedback voltage. The feedback voltage is used to control the U1circuit as a current source, as desired. Resistors R1 and R2 set thevoltage feedback level to the U2 circuit.

In an alternative embodiment of the invention, a buck converter powersupply 300 might be utilized to provide a constant power load on theultracapacitors and provide a constant current to any LED element. Abuck converter topology, as illustrated in FIG. 11, somewhat resemblesthe buck-boost topology, as set forth in FIG. 10 with like elementssharing like reference numerals. The power path from the PWM circuit U1includes a Schottky diode element D1 and inductor L1, as illustrated.The buck converter circuit 300 might be utilized if the LED light enginevoltage requirement is less than the ultracapacitor stack voltage.

Alternatively, if the LED light engine voltage requirement is greaterthan the ultracapacitor stack voltage, a boost converter topology mightbe utilized. For example, the boost converter circuit 400, asillustrated in FIG. 12, might be used to drive the LED light engine.FIG. 12 resembles FIG. 10, with like reference numerals being utilizedfor like elements. In the boost topology of circuit 400, a solid stateswitch Q1 provides the functionality to turn the power supply ON/OFFbased on the control of switch S1. Such a switch Q1 might also bedesirable for circuits 200 and 300 as well. Schottky diode D1 andinductor element L1 are coupled appropriately for the boost converteroperation.

In the circuits of FIGS. 10-12, 15, 16, PWM circuit U1 can be a standardbuck, boost, or buck-boost PWM circuit that can operate at low voltages,such as from 1.5 Volts to 12 Volts. In each of the five circuits, the U2circuit element is utilized to control the voltage feedback to the PWMU1 to provide the current source function. The voltage across the R3element is directly proportional to the current through the LED, and theerror amplifier amplifies the small voltage drop across the low Ohmsensing resister R3 to equal the internal PWM reference voltage. The U3circuit is a control circuit that controls the ON time of the lightengine and the shutdown when the ultracapacitor has discharged to apoint that is too low for use by the PWM circuit U1. The U3 circuitcould be a microprocessor, microcontroller, complex programmable logicdevice (CPLD), or a simple analog timer, such as a ZSCT1555. The U4circuit is a charge pump power supply that acts as a low powerbuck-boost controller, and provides a stable, constant supply voltage tothe control circuit during the discharge of the ultracapacitor. The Q1circuit acts as a solid state switch to disconnect the LED power supplyfrom the ultracapacitors when the power supply is turned OFF. The powercircuit 400 illustrated in FIG. 12 utilizes the Q1 element. Such a solidstate switch Q1 may or may not be necessary with the buck converter ofFIG. 11 or the buck-boost converter of FIG. 10. Inductor element L1 isan electronic element required for the switched power mode power supply(SMPS). The value of L1 could range generally from 1 μH up to 300 μH.The D1 element, as noted above, is a Schottky diode that generally wouldbe utilized for the buck or boost converter configurations of FIGS. 11and 12.

FIG. 15 illustrates and alternative current source for powering the LEDlight engine in accordance with an embodiment of the invention. FIG. 15illustrates a flyback current source 600, wherein similar elements areused, as noted above, with respect to other embodiments. In FIG. 15, T1indicates a flyback transformer and element Q2 illustrates a flybackswitch, wherein resistor R4 is a current limit sensing resistor forswitch Q2. In operation, when the switch Q2 is ON, the primary of thetransformer T1 is directly connected to the input voltage source. Thevoltage across the secondary winding is negative, so the diode D1 isreverse-biased (i.e., blocked). The output capacitor supplies energy tothe output load, such as LED 1. When the switch is OFF, the energystored in the transformer is transferred to the output of the converter.The feedback signal from the current sensing resistor R3 is sent back tothe PWM circuit U1 to control the LED current.

FIG. 16 illustrates another alternative current source in the form of a“single-ended primary inductor converter” (SEPIC) converter 700. A SEPICconverter is a type of DC-DC converter that allows the electricalvoltage at its output to be greater than, less than, or equal to, thatof its input. The output of the SEPIC converter is controlled by theduty cycle of the U1 circuit from the feedback signal from current senseresistor R3 that is sent back to the U1 PWM circuit to control the LEDcurrent. Similar references are used in FIG. 16 as used in FIGS. 10-13and 15. Q1 is a solid state switch that turns the power supply ON/OFF.The split inductors L1 and L2 provide the boost function (L1) and thebuck function (L2). Capacitor C4 provides AC coupling in the circuit ofFIG. 16.

While the various FIGS. 10-13, 15, 16 illustrate two ultracapacitors C1and C2 in series, a single ultracapacitor might be utilized, as notedabove. Alternatively, the ultracapacitors C1, C2 might be connectedtogether in parallel. Still further, more than two ultracapacitors mightbe utilized, and they might be coupled together in a series-parallelarrangement to provide the required voltage and power for the lightdevice 10.

In an alternative embodiment of the invention, the circuit asillustrated in FIG. 13 might be utilized, such as for providing power tolower power LEDs for applications other than curing dental compounds.Circuit 500 in FIG. 13 is in the form of a boost converter, which ispowered by ultracapacitors C1, C2. A voltage detector portion of thecircuit provides power to a “Ready” LED (See FIG. 1A) to indicate thatthe light device 10 is fully charged. An ON/OFF switch portion powers atimer circuit, which drives a solid state switch Q2 to turn the powersupply ON and OFF after a selected period of time (e.g., 5-40 seconds).A boost converter then provides the necessary power to an LED or LEDarray as shown.

While the present invention has been illustrated by the description ofthe embodiments thereof, and while the embodiments have been describedin considerable detail, it is not the intention of the Applicant torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details representative apparatusand method, and illustrative examples shown and described. Accordingly,departures may be made from such details without departure from thespirit or scope of Applicant's general inventive concept.

What is claimed is:
 1. A curing light device for curing a compound, thecuring light device comprising: a housing; a tip structure configured tobe removably coupled with the housing, the tip structure having aproximal end and a distal end; at least one light emitting deviceoperable for emitting light in a wavelength range suitable for curing alight curable compound, the at least one light emitting devicepositioned at the distal end of the tip structure; electrical componentspositioned at the proximal end of the tip structure and coupled with theat least one light emitting device, the electrical components configuredfor engaging complementary electrical components positioned in thehousing for providing power to the at least one light emitting device; aportion of the tip structure extending beyond the proximal end of thetip structure, the tip structure portion configured to be received by afeature in the housing for physically aligning the tip structure in thehousing and for aligning the complementary electrical components in thetip structure and housing to transfer power from the housing to the tipstructure; a power supply circuit positioned in the housing and operablycoupled with the electrical components positioned in the housing, thepower supply circuit being rechargeable and including at least oneultracapacitor element for being charged.
 2. The curing light device ofclaim 1 wherein the portion of the tip structure extending beyond theproximal end of the tip structure is centrally located in the tipstructure for physically aligning the tip structure in the housing. 3.The curing light device of claim 2 wherein the electrical components arepositioned around the centrally located portion of the tip structure forbeing aligned with complementary electrical components of the housingwhen the tip structure is removably coupled with the housing.
 4. Thecuring light device of claim 1 wherein the portion of the tip structureextending beyond the proximal end of the tip structure includes at leasta portion of a heat sink thermally coupled with the at least one lightemitting device.
 5. The curing light device of claim 4 wherein thefeature for receiving the tip structure portion includes a channelformed in the housing, the channel including a heat sink to thermallycouple with the heat sink portion of the tip structure.
 6. The curinglight device of claim 1 wherein the power supply circuit includes acurrent source circuit coupled between the ultracapacitor element andthe electrical components that is configured to discharge the at leastone ultracapacitor element as a current source for driving the at leastone light emitting device, the current source circuit including at leastone of a buck converter circuit, a boost converter circuit, a buck-boostconverter circuit, a flyback circuit and a single ended primary inductorconverter (SEPIC) circuit.
 7. The curing light device of claim 1 whereinthe tip structure is formed of an autoclavable material capable ofwithstanding autoclaving.
 8. The curing light device of claim 1 whereinthe tip structure includes a heat sink extending from the at least onelight emitting device at the proximal end to at least the distal end andinsulative material covering the heat sink between the proximal end andthe distal end.
 9. The curing light device of claim 1 wherein the tipstructure includes at least one of a transparent element or a lens forsealing the tip structure distal end proximate the at least one lightemitting element.
 10. The curing light device of claim 1 wherein theelectrical components of at least one of the tip structure and housingare circular and can engage complementary electrical components over arange of 0° to 360°, so the tip structure may be rotated with respect tothe housing.
 11. The curing light device of claim 1 wherein at least oneof the electrical components of the tip structure or housing includesspring contacts to ensure engagement between the complementaryelectrical components.
 12. A curing light device for curing a compoundcomprising: at least one light emitting device operable for emittinglight in a wavelength range suitable for curing a light curablecompound, the at least one light emitting device positioned at a distalend of the curing light device; a heat sink system thermally coupledwith the at least one light emitting device for removing heat therefrom,the heat sink system including a solid element thermally coupled with aphase change element, the solid element cooperating with the phasechange element to remove heat from the at least one light emittingdevice.
 13. The curing light device of claim 12 wherein the solidelement is thermally coupled with the at least one light emittingdevice.
 14. The curing light device of claim 12 wherein the phase changeelement includes a reservoir portion containing an amount of phasechange material capable of absorbing heat.
 15. The curing light deviceof claim 14 further comprising a channel coupled with the reservoirportion, the channel configured for engaging with the solid element fortransferring heat from the solid element to the reservoir portion. 16.The curing light device of claim 14 wherein the phase change materialincludes at least one of paraffin wax or paraffin wax with carbon. 17.The curing light device of claim 12 further comprising a housing and atip structure configured to be removably coupled with the housing, theat least one light emitting device positioned at the distal end of thetip structure, the solid element of the heat sink system being locatedin the tip structure.
 18. The curing light device of claim 17, the phasechange element being located in the housing, the solid element thermallycoupling with the phase change element when the tip structure is coupledwith the housing.
 19. The curing light device of claim 18 furthercomprising a channel in the housing thermally coupled with the phasechange element, the channel configured for receiving a portion of thetip structure when the tip structure is coupled with the housing. 20.The curing light device of claim 19 wherein the phase change elementincludes a reservoir portion containing an amount of phase changematerial capable of absorbing heat, the channel thermally coupled withthe reservoir.